Here is a tutorial on how to play Pokemon GO on your PC.

Step 1:
Download a program called Nox: [ Register or Signin to view external links. ]

Step 2:
This isn't required but you can download the Pokemon APK on the same website above. If you don't want to just download it from the Play Store.

Step 3:
Install the program and once you get to the nox app player you have to root it. To locate that click the cog emblem next to the minimize button. Once in there under root click the drop down arrow and turn it on.
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Step 4:
While still in the setting menu click the Advanced tap and choose the setting you think your computer can handle. For better gameplay put your performance settings on High and Startup Settings on Tablet/1080p. Then save your settings and then restart the program.
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Step 5:
After you have done that, if you haven't already install Pokemon GO. Before you open the program you have to make sure you have turned off your location in your computer settings. For Windows 10 just go to Settings above the Power icon on your Windows menu
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Step 6:
After you have turned off your location go back to the Nox app player and click the location icon on the right side of the program. (Looks like a google location pin.). It is the 4th icon from the top.
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Step 7:
On the location menu choose a location in which you want to be located. (I recommend using an area near you and not to move long distances at a time because it will get you soft banned and you wont be able to do much until it unbans you). When ever you haave selected your desired location click the OK button at the bottom right of the location settings.
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Step 8:
You can leave the location settings open to change your location at anytime, but don't move large distances too quickly. I recommend a few KM's at a time. Now startup Pokemon GO.

Step 9:
I suggest making a new account due to the fact this does break the ToS of Niantic you agree to play the game and it can get you banned. When trading is available you can trade the Pokemon you have caught to your main account.

Step 10:
After that you're all set to play Pokemon GO.


IMPORTANT!:
Do this at your own discretion as said above this does break Niantic's ToS and is GPS spoofing.

If you want to find rare Pokemon in your area here is a live map that shows "most" of the Pokemon in your area. [ Register or Signin to view external links. ]

Here is a better tutorial if this one is too confusing or not in depth enough

Text tut: [ Register or Signin to view external links. ]

Video Tut: